1. Field of the Invention
The present invention relates to an ink jet recording device in which an ink carrier film is formed to have a plurality of pores or recesses, the pores or recesses are filled with ink, the film filled at their pores or recesses with the ink is quickly heated by such a heat supply source as a thermal head according to picture image information to generate bubbles within the ink in the heated pores or recesses and to eject the ink onto a recording medium under influence of the pressure of the bubbles for recording, and more specifically, to an improvement in the structure of an ink carrier film in use with such an ink jet recording device, which enables improvement of its thermal efficiency and minimization of frictional wear of a heat supply source.
2. Description of the Prior Art
Conventionally, there have been proposed various recording systems ranging from impact types to non-impact types. Non-impact type systems, which provide less noise than the impact type systems, include electrophotographic, electrostatic, thermal and ink jet systems. Among non-impact type systems, the ink jet recording system is highly excellent in that it has many advantages of less noise, low power consumption, easy miniaturization, easy modification to colour arrangement and inexpensive constituent elements. According to the ink jet system, in general, very small ink drops are ejected from capillary tube nozzles for printing on a recording paper. There have been proposed an ink jet system (Japanese Patent Appln. Laid-Open Publication No. 48-9622) wherein the vibration of a piezoelectric element within an ink chamber is utilized to instantaneously boost the pressure of the ink liquid and to eject the ink from nozzles, and an ink jet system (Japanese Patent Publication No. 56-9429) wherein heating elements are provided within an ink chamber to generate bubbles in the ink chamber and boost the pressure of the ink liquid for ejection of the ink from nozzles. These systems are called "on-demand" systems which allow ink ejection only when ink is required and ar advantageous in its less ink consumption and relatively high recording speed. The on-demand system, on the other hand, has big problems that manufacturing of the recording head is complicated including the formation of pores in the nozzles and disposition of the piezo-electric elements and heating elements within the ink chamber, and that the stoppage of the system causes solidification of ink liquid and thus the clogging of the nozzle pores, resulting in its operation failure. As a recording system of ejecting ink without using such nozzles, there has been suggested in Japanese Patent Appln. Laid-Open Publication No. 51-132036 a system in which abrupt heating of ink by heating elements provided in the ink liquid causes generation of air bubbles and the bursting impulse of the air bubbles causes ejection of ink drops from the liquid surface. This system can resolve essentially the clogged-ink problem, but has been unsatisfactory in that the evaporation of ink involves environmental pollution problems and many restrictions on the system arrangement, ink leakage occurs during transportation or shift of the system from one place to another, and ink drops tends to become an unstable state because it is difficult to keep constant a distance between the ink surface and the heating section thus lowering the recorded picture quality. As another system without using nozzles, there has been proposed a system such as disclosed in Japanese Patent Application No. 58-178201, in which as an ink carrier film having a plurality of pores or recesses formed therein is passed through an ink supply section, the pores or recesses are filled with ink so that when the ink-filled pores or recesses reach the surface of a thermal head, a voltage is applied to the thermal head to quickly heat them and generate bubbles in them, whereby the pressure of the generated bubbles causes ejection of the ink in the pores or recesses toward a recording paper for recording. However, this proposal involves such a problem that the ink carrier film used in the system is usually made of metal, thus causing a low thermal efficiency and fast frictional wear of the thermal head.
In view of the above circumstances, it is an object of the present invention to provide an improvement in the structure of an ink carrier film with an improved thermal efficiency and a less frictional wear of such a heat supply source as a thermal head.